what was the very first moment that harry got inbetween janeway and winning, or even getting home in the 19 episodes before Non Sequitor?
He made no impact.
The only Harry episode before non sequitor is Emanations which is about how he fell overboard and then shat on the Prime Directive on his was back to the ship, which is totally a zero sum game.
I don't think any one liked writing Harry stories or there would have been more Harry stories. Which is probably why they were going to kill him off.